Transmission system



June 15, 1937. E. KsEMANN TRANSMISSION SYSTEM Filed March 30, 1955 2 Sheets-Sheet l INVENTK:

E. KSEMANN TRANsMlssloN SYSTEM June 15, l1937.

Filed March 30, 1953 2 Sheets-Sheet. 2

Patented June l5., 1937 TRANSMISSION SYSTEM `Erwin Ksemann, Steinstucken, near Berlin,

Germany Application March 30, 1933, Serial No. 663,574

' In Germany January 20, 1933 7 Claims. (Cl. 179-15) My invention relates to improvements in transmission systems and more particularly to a method of producing distorting and compensating cur-A ing current opposite in phase Vto the distorting current, and that said distorting and compensating currents are produced by picking up at each of said stations, a single point of a single finite phonograph record. These transmission systems have been found to be vunable to fulnll their purposes of maintaining the desired secrecy, since the individual records of a single phonograph record picked up at only a single point, repeat after a certain time, so that unauthorized persons may easily determine the distorting alternating currents by oscillographing the transmitted messages and then may decipher further messages. Moreover, it is impossible to give the distorting or compensating currents produced by picking up a single point of a single phonograph record any desired shape of curve. Thesecurrents, however, will have always the shape of curve of the used phonograph record.

With the foregoing in mind it is an object of the present invention toA provide a method in the transmission of messages, which entirely prevents a deciphering of the transmitted messages by unauthorized persons.,

Another object of the present invention is' to provide a method of producing distorting and compensating currents, which allows the shape of curve of said currents to vary in any desired manner, although phonograph records with unvariable records are used, so that, even if the phonograph records used would be'known to an unauthorized person, the latter will not be able to decipher the messages.

I accomplish the purposes of my invention by a method which consists in producing the distorting andcompensating currents used in the above described method for maintaining secrecy in the transmision of messages by picking up one or .former by the transmission line I0.

more phonograph records at the sending station and the receiving station at a plurality of places phonograph record. Thus, the resultant curves of the distorting or compensating current, which are a function of two or more points of the phonograph record, are entirely different from the original curve of the used phonograph record, and without knowledge of the relative position of the picking up points to each other, it is impossible to decipher the transmitted messages. 10

Another feature of my invention is to -vary the relative effective position of said picking up points to each other' during the picking up operation, so that a deciphering by unauthorized persons is rendered still more diflicult. 15

In the accompanying drawings which form a part of this specification and in which like characters of reference indicate the same parts:-

Fig. 1 is a diagrammatical view of an arrangement of a transmission system embodying the features of my invention, whereby single phonograph records with two picking up points are used at the sending and receiving stations;

Fig. 2 is a diagrammatical View of the device producing distorting or compensating currents, showing the use of two phonograph records with one picking up point for each phonograph record;

Fig. 3 is a diagrammatical plan View of a plate carrying a record; and

Fig. 4 is a diagrammatical side elevational view, showing the arrangement of the plate carrying the record in combination with photoelectrical means to pick up the record.

Referring to Fig. 1, A designates a sending station, and B, a receiving station connected to the 35 The telephone variations produced in the circuit II by the operation of the microphone I2 at the sending station A will be transmitted through the transformer I3 to the line I 0. The message current outgoing from the microphone I2 is undistorted during its flow through the circuit I I. In order to maintain secrecy in the transmission of the messages between the stations A and B, a device I4 is provided, which produces a distorting alternating current to be superimposed on the outgoing message current, so that a distorted and unintelligible currents iiows through the transmission line I0. Said device I4 comprises a motor I5, to the shaft I8 of which a plate I'I carrying 50 arecord is secured. The motor I5 rotates the plate I1, and the phonograph record is contacted at two points I8 and I 9 by suitable means comprising for example a transmitter provided with a needle. The transmitters I8 and I9 are connected to each other and to the circuit 20, which in turn is connected to the winding I3!)4 of the` transformer 'I3 and includes an amplifier 2| if desired. Thus the transmitters produce a distorting alternating current in the circuit'gZll; and the resultantl curve of which is a function of two points of the phonograph record,v so that this curve is entirely different from the original curve of the phonograph record, The distorting current of the circuit 20 is superimposed on the outgoing message current by the transformer I3, so that a distorted current flows through the line I0. In order to neutralize thee'ffect of the superimposed distorting current at the receiving station B, the latter is equipped with a device I 4'.' which produces a compensating alternating current to be superimposed to the distorted current arriving from the line I0. Said device I4' com-` prises a motor I5', which is connected to the motor I5,of the device I4 through a circuit 22 in such a way, that the motors will operate synchronously. The shaft I6' of the motor I5 carries a plate II' provided with a record and identical to the plate II of the device I 4 at the sending station A. During the rotation `of the plate I'I' driven by the motor I5', the phonograph record is picked up at two points I8' and I9', the effective positions of which being spaced apart from each other the same distance as the positions of the points I8 and I9. The phonograph transmitters I8' and I9 are connected to each other and to the circuit Q28', which in turn is connected to the winding |30', of the transformer I3 and includes amamplifier 2 I if desired. Thus the transmitters produce a compensating alternating current in the circuit 20', and the shape of curve of said compensating current is equal to the shape o`fcurv'e of the distorting current. The connection of the circuit 20 to the Winding 30 of the transformer I3 is made in such a way, that the phase of the compensating current superimposed on the arriving distorted current by the transformer I3' is displaced at an angle of 180 with respect to the phase of the distorting current. Thus the" effect' of the distorting cur` rent is neutralized, and the receiver I2! connected to the transformer I3 through the circuit I I will respond only t`o the telephonic variations transmitted from the microphone I2 of the sending station A. The distorted currents in the transmission line II), however, are entirely unintelligible to anyone who might have access to the line I8.

It is obvious that the station Amay also be equipped with a receiver and the station B with a transmitter, by a simple supplement of thewire connections, so that each of both stations forms a sending and receiving station.l Furthermore,

the microphones andy receivers may be replaced by telegraph keys and recorders respectively, so

that the described transmission system serves to ,maintain secrecy in the transmission of signals.' Moreover ,the metallic transmission line I l) may be replaced by any wireless transmission system. The. relative effective positions of the picking `up points I8, I8 and` I8 and I9 to eachother may be adjusted) according to a certain key agreed between the two stations. In order to render an undesired deciphering still more diffi-1 cult; preferably the relative leffective positions of said picking up points I8, I 9 and I8', I9' to each other are continuously varied "in synchronism with the movement of the phonograph records during the operation. .l

While Fig. 1 shows the usel of a single phonopersons is impossible, even if the phonograph records used would be known. It is obvious that also ay single phonograph record with three or even more picking up' points or several phonograph records with one or several picking up points may be used to produce the distorting and compensating currents respectively.

' The records to be used may be either of the nite type, such as a usual phonograph record, or of the endless type, such as a plate with an endless record curve 24 (Fig. 3) or an endless band with a record curve. Under certain cir cumstances, it may be advisable to use a single record of the endlessy type with a single picking up point at eachmoi' the stations, and such an arrangement has yet the advantage that the adjustment of the synchronism of the records at the stations is considerably facilitated in comparison with the records of the finite type as hitherto used.

The means carrying the records maybe formed by an iron disc provided with an irregularly serrated circumference and rotated in a magnetic eld or by phonograph records or endless bands. which have a record. Preferably, however, a plate of transparent material provided with a record is employed, which allows the record curve to be picked up by a photo-electrical ray. Fig. 3 shows' such a glass plate 25 carrying on its surface a photographic emulsion layer, on which a complicated distorting noise is recorded by means of the so-called transverse method, and Fig. 4 illustrates diagrammatically the arrangement of such a transparent plate in a photoelectrical device. A'light source 25 is arranged in front of the glass plate 25 mounted on the shaft I6 of the motor I5, and a photo-sensitive cell 2Iy is disposed behind the rotating glass plate 25. The record, 24 disposed on the plate 25, is lighted by the light source 26, and the photosensitive cell 21 receives the light rays passed through the record and transforms the same into electrical currents led to the circuit 28. 'I'here are three gaps I, 2, and 3 shown in' Fig. 3 through which light rays may pass to photo-sensitive cells correspondingly arranged, behind the plate 25, so that the records .24 are picked up at three points by photo electrical ray.

.r The phonograph records I'I are replaceably arranged on the shaft I6, so that at different times,

Endless phonograph records are rotated with such a number of revolutions, that the fundamental frequency resulting from the number of ldifferent phonograph records may be employed.

of the phonograph records, especially' that of the phonograph record at the sending station, is used to impart an impulse to the means driving the other phonograph record, so that the latter positively and synchronously followsin its movements to the movements of the former. Furthermore, suitable adjusting devices may be provided, by means of which at the receiving station, the desired synchronism may be established, after the movement of 'the phonograph'record has been started.

In order to avoid an overcompensation, the intensity of the distorting alternating currents may be determined by controlling means being independent of 'frequency Furthermore, any line distortions, to which the distorting alternating current is subjected, may be eliminated at the receiving station byso-called artificial lines or combinations of ohmic capacities and inductive re- 20 sistances, which are connected in the circuit of the compensating alternating current.

From the foregoing disclosures an important feature of my new method is that the shape of curve of the produced distorting or compensating current is lentirely different from the shape of curve of the phonograph record or phonograph records used. As the phonograph record or phonograph records are picked up at a plurality of points, the shapeof curve of the produced current will be always a function of a plurality of points of the curve of the phonograph record or Furthermore, the resultant phonograph records. curves of the currents may be different for each operation, although the same phonograph record or phonograph records are used, if the relative effective positions of the picking up points will. vbe changed.

I have shown a preferred embodiment of my invention but it is clear that numerous changes and omissions may be made without departing from the spirit of my invention.

I claim:-

1. A transmission system for maintaining secrecy in the transmission of `messages between a sending station and a receiving 4station by distorting the outgoing message currents by superimposing thereon at the sending station a distorting alternating current and by neutralizing the eiect of said superimposed current at the receiving station by superimposing on the distorted current at the receiving station a compensating alternating current opposite in phase to the distorting current, comprising at each of said stations, means including a phonograph record, and a plurality of pick-ups adapted to pick up said phonograph record at a plurality of places thereon to produce said distorting and compensating currents respectively.

2. A transmissionsystem for maintaining secrecy in the transmission of messages between a sending station and a receiving station by distorting the outgoing message currents by superimposing thereon at the sending station a distorting alternating current and by neutralizing the eiect of said superimposed current at the receiving station by superimposing on the distorted current at the' receiving station a compensating alternating current opposite in phase to the dissecrecy in the transmission ormessage's between a. sending station and a receiving station by dis- Vplaces thereon to produce said distorting and compensating currents respectively.

4. A transmission system for maintaining secrecy in the transmission of messages between a sending .station and a receiving station by distorting the outgoing message currents by superimposing thereon at the sending station a distorting alternating current and by neutralizing the eiect of said superimposed current at the receiving station by superimposing on the distorted current at the receiving station a compensating alternating current opposite in phase to the distorting current, comprising at each of said stations, meansA including an endless phonograph record, and a pluralityof pickups adaptedt pick up said endless phonograph record at a plurality of places thereon to produce said distorting and compensating currents respectively.

5. A transmission system for maintaining secrecy in the transmission of messages between a sending station and a`receiving station by distorting the outgoing message currents by superimposing thereon at the sending station a distorting alternating current and by neutralizing the effect of said superimposed current at the receiving station by superimposing on the distorted current at the receiving station a compensating alternating current opposite in 'phase to the distorting current, comprising at each of said stations, means including a phonograph record, and

a plurality of photo-electrical pickups adapted to secrecy in the transmission of messages between a sending station and a receiving station by distorting the outgoing message currents by superimposing thereon at the sending station a distorting alternating current and by neutralizing the eiect of said superimposed current at the receiving station by superimposing on the distorted current atthe receiving station a compensating alternating current opposite in phase to the distorting current, comprising at each of said stations, means includi'ng a phonograph record, a plurality of pickups adapted to pick up said phonograph record at a plurality of places thereon to produce said distorting and compensating currents respectively, and means for simultaneously varying the relative effective positions of said places to each other.

'7. A transmission system for maintaining secrecy in the transmission of messages between a sending station and a receiving station by distorting the outgoing message currents by superimposing thereon at the sending station a distorting alternating current and by neutralizing'the stations, movable means including a phonograph record, a plurality 'of pickups adapted to pick up said phonograph record at a. plurality of places thereon to produce, said distorting and compensating currents respectively, and rneans for simulthe distorting current.- comprising at each of said f taneously and continuously varying the relative effective positions of said places to each other in synchronism with the movement of said means including a phonograph record.

ERWIN KSEMANN. 

